Skip



Aug. 25,1953 A. FINLAY ET AL SKIP 3 Sheets-Sheet 1 Filed March 26, 1951 INVENOR. ALEXANDER FuNLAY James W- xl irl BY CLARK %%Mf ATTORNEY Aug. 25, 1953 A. FINLAY ETAL 2,649,983

SKIP

Filed March 26, 1951 s Sheets-Sheet g INVENTOR. ALEXANDER FINLAY BY JAMES CLARK A-r-roRNa Aug. 25, 1953 A. FINLAY ETAL SKIP Filed March 26, 1951 3 Sheets-Sheet 3 INVENTOR. Auzxnmoen FINLAY Jamas W. v(LuaRK Ar-roaoaav i atented Aug. 25 1953 SKIP Alexander Finlay and James W. Clark, Marquette, Mich., assignors to Lake Shore Engineering Company, Iron Mountain, Mich., a corporation of Michigan Application March 26, 1951, Serial No. 217,636

8 Claims.

This invention relates to a skip which dumps from the bottom rather than the top.

The present skip is particularly advantageous in connection with shaft mines. The usual shaft mine employs two skips so reeved on the hoist mechanism that the weights of the skip offset each other. The conventional mine skip is overturned in the headframe to dump the ore into a bin over the crushers. Since the skip must be slowed down prior to entering the dump scrolls, which impart the overturn motion to the skip, and must be moved slowly while being overturned and returned to the guide timbers, the dump time of the duty cycle is quite long. When it is realized that under modern mining methods the output can easily exceed the capacity of the skips to hoist the ore to the surface, it is readily apparent that reducing the duty cycle time makes pos-- sible more cycles and increased production with little or no increase in labor.

An object of this invention is to provide a bottom dump skip which requires less dump time than the conventional skips. This reduced time has, in one case, indicated a possible 7 /2% increase in output by permitting the number of duty cycles per shift to be increased. The reduced time per duty cycle is also reflected in another situation. Thus it ha been generally assumed that the limit of shaft depth was about 2500 feet since the time required to hoist ore to the surface from greater depths made operation uneconomical. Now, however, shafts may be sunk deeper and the mine still operated profitably. It is estimated that with the present skip the limit may be about 3500 feet. There area number of mines in this country which have pretty well exhausted the ore to 2500 feet and which have high grade ore below that level.

Another object is to provide a skip which reduces the strains on the headframe and timbers and the necessary headframe height over the bins. Conventional skips severely stress the headframe and guide timbers going into and coming out of the dump position. Furthermore, the hoisting distance over the bin and, therefore, the headframe height over the bin is relatively great where the skip must be overturned. The present skip goes into and out of the dump position smoothly and the stresses on the headframe and guide timbers are greatly reduced. This means that new structures require less bracing, etc. with a consequent saving in steel and fabrication costs. In the case of old structures the existing headframe can now handle greater tonnage and the existing headframe height permits of larger skips which have such increased capacity.

Another object is to provide a skip which maintains better counterbalancing on the hoist mechanism. Most of the Weight of a conventional skip is carried by the dump scrolls in the dump position and the hoist is subjected to a greater load since the skips are not counterbalanced. Most of the Weight of the present skip is carried by the hoist in the dump position and the hoist is, therefore, better counterbalanced.

A further object is to provide a skip which dumps clean and fast. This skip can handle wet, sticky ore without having the ore hang up on the sides of the skip when it is dumped.

Still a further object is to provide a bottom dump skip in which leakage and spillage is substantially non-existent.

Another object is to provide a bottom dump skip which has a simple, positive-acting door permitting compensation for wear and adjustment of its action.

Still another object is to provide a kip which travels smoothly in the timbers without whip or lash, thus making greater hoisting speeds feasible.

Other objects and advantages will be pointed out in, or be apparent from, the specification and claims, as will obvious modifications of the single embodiment shown in the drawings, in which:

Fig. 1 is a side elevation of the skip with the middle portion broken away;

Fig. 2 is a front elevation of the skip shown in Fig. 1;

Fig. 3 is a fragmentary view of the skip in the dump scroll;

Fig. 4 is a section taken on line 44 of Fig. 1 and includes the guide timbers;

Fig. 5 is a fragmentary section on line 5-5 of Fig.2;

Fig. 6 is a fragmentary View taken as indicated by line 66 on Fig. 5;

Fig. 7 is a fragmentary section on line 1-! of Fig. 1;

Fig. 8 is a section on line 8-8 in Fig. 1 to show the wear bars cooperating with the timber;

Fig. 9 is a side elevation of the entire skip to give the relative proportions; and

Fig. 10 is a schematic view showing the skip pivot, door, and toggle mechanism in solid lines with the other parts of the skip in dotted line.

Referring to the drawings in detail, the skip comprises a body it) pivotally supported by stringer l2 at pivot I4 to move from its normal position as shown in Figs. 1 and 9 to the dump position shown in Fig. 3 while the stringer remains engaged with the guide timbers or rails 16 fixed in the shaft. Stringer I2 is a framework comprising a pair of parallel spaced channels it, it and a diagonal bracing channel 2?: on each side of the body and interconnected at the top by means of a plate 22 welded to the channels and at the bottom by means of a plate it. A transom channel .25 interconnects the side channels at the'top of the frame and a similar transom 23 connects the bottoms. Wheels 353 are rotatably carried on bell cranks 32 at the top and bottom of the stringer frame to engage the guide timbers i6. Spring 34 is compressed between one end of crank 32 and support 36 to bias the wheels into contact with the timbers to yieldingly absorb shocks-as the skip is hoisted in the shaft and reduce the strain on the timbers. Wear bars 3'5, 38, 39 may be mounted adjacent the top and bottom of each stringer frame to loosely engage the timbers as shown in Fig. 8. In large skips the wear bars may serve to limit movement'of the stringer with respect to the timbers andin smaller skips the wear bars may be employed to the exclusion of wheels 33. These wear bars are preferably'bolted or otherwise remova'bly secured to permit their replacement when worn. "Rope 'thimble 48 is mounted inthetop-transom and receives wire rope connectedto the hoist mechanism.

The long skip "b'ody illisprovided-with an open top and front to permit rapid loading of the skip. Rubber deflector plate i l, hung from the transom, prevents ore from striking the thirnble. Rearwardly andupwardly-inclined plate 33 at the top opening prevents spillage during loading and catches falling ore, if any,'in the shaft.

It will be noted that pivot is is positioned-rearwardly of -the vertical body axis. Therefore, the weight 'ofbody ldbiases'thebo'dyinto the stringer. A pair of stop blocks as are mounted on channel i] extending across the rear of guide channels .52 welded to "the inside of stringer channels 18 and 20 and suitably braced by means of plate 53, and limit rearward movement of the body. Guide channels 52, it will be noted, project upwardly at a: slightangle and are adapted to cooperate'with guidebarfit welded to each side of body it! to prevent uneven movement of the body out of the stringer frame as it moves to the dump position. Where desired, wear .plate 53 may be removably mounted inside channel 52.

Imm diately below guide channel 52 the front stringer [:8 is partially-cutout to permit angular latch plate 69 to pass through the channel to engage the back of the timber when the skip is in the shaft. The .ffront stringer channel it is reinforced by plate '82 welded to the outside leg of the channel adjacent the cut-out portion. Since latch plate til normally co-acts with the guide timber as shown in Fig. lto prevent move-- ment of the body toward the dump position, it will be appreciated that a portion of the guide timbers must be cutout in the proximity of the dump position to permit the latch plate to move through the opening as'the-body moves into its dump position. Thus when the dump rollers 64 at the lower front portion of each side of body it engage the dump :scrolls 66 in the headframe, not shown, to start the movement of the body to its dump position, that portion of the guide timber adjacent latch plate 83 at the moment must be cut out toperrnit the latch plate to move through the opening. As the body returns to the stringers the latch plate again passes through the openings and latches the body with respect to the timbers.

The usual striker bars 58 are provided on body it. Door iii is mounted on pivot i2 positioned rearwardly and upwardly of the bottom edge of body if) to allow the door it! to move down and. back from the opening when dumping, thus facilitating a clean dump. In order toprevent spillage to the side as the door opens, the body is provided with depending, quadrant-like skirts at.

The door opening and closing movement is regulated by means of links or levers l6 pivotally connected to the door at 18 and to adjustable supports .863 carried by plates 8| which are part of a parallel linkage. Thus pivots 82, 82 on each plate are connected to parallel links 83,

pivotally mounted on stationary uprights 8A,

2 The uprights are Welded or otherwise secured to stationary plates 85 mounted on bottom trancom 28 and supporting adjustable pivot on vertical adjustable jack screw apparatus'flfi whi'ch permits vertical adjustment of the height of'pivot to in a manner known in other machine arts. Actuation of the jack screw will move the :pivot over a predetermined path to adjust the :action of toggle lever and compensate foriwear. We have found that if the center of :door pivot 18 is approximately one iinch'behind the imaginary line is connecting the centers of adjustable pivot and body pivot i l (see Fig. '10 where the'upward divergence of imaginary line 19 and imaginary 8i connecting the pivot fill and "door pivot 78 illustrates the rearward disposition of door pivot '18 when the door is'c'losed) the desired toggle action will 'resiilt to open the 'door slowly as thebody s'tarts'toward the-dump position and rapidly in later stages of the dumping action. IndeedQthetoggle action keeps the "door closed in the veryearly stage 'of movement. The toggle action allows the body tobe moved over the lip of the bin before dumping starts. Furthermore, anybody sway relative to the stringers in the shaft will not-cause the door to crack open to spill ore down the shafts.

Fig. 3 illustrates'the steep dumping angle of this skip which helps insure 'a clean dump with no ore hanging on thesides ofithebody. 'We have found that in the case of wet, sticky ore it may be beneficial to line the body withru'bber sheets 8? secured at their .upper edges and overlapping "in the manner of clapboard siding to prevent ore hanging on the sides since they shake enough during the dumping-action to dislodge all the ore therefrom.

The handlingof Wet oreraises another ,problem with respect to a skip of this type in that leakage from the bottom must be prevented. 'We employ various seals about the bottom opening dependent upon the'location of the seal. The front of the bottom opening is provided with a rubber seal .88 'boltedibetweenbody'l0 and an auxiliaryplatetS. .Th'issealfis adapted to be compressed by "thesteel plate 9.8 .on the top surface of doorlil to seal the front edge of the opening. A piece of bar, stock 94., .weldedbottom rear edge of the opening, compresses the thick portion '93 of rubbersheet "Bl sandwiched between the top door plate Wand the bottom plate 92 to seal the rear of the opening.

Referring now to Fig. 7, door 10 is wider than the body iii and is: provided with a scrapers? .at each side to clean ore from the inside of skirt 14 as the door closes. Rubber skirts .96, hanging on the outside of body .16, .seal the space between thescraper and body I'ltwhen the door is closed. The weight of the ore in the body tends to force skirts '96 from this space and makes the seal more effective. It has been found that in some cases the labyrinth formed by means of the projection of the scraper edge 95 above the lower-edge of the body serves to effectively seal the bottom edge Without the use of skirt 96 or other means even though the ore may be wet. It appears that the weight of the ore compacts the ore at this opening to such an extent that leakage is substantially precluded. The adjustability of the door afforded by the jack screws permits maintenance of a tight metal-to-rubber seal about the door at all times.

As pointed out above, scrapers 95 on each side of the door clean off the inside of skirts 14 as the door closes. It will be noted that the space above the scraper and skirts 14 is open to permit any ore picked up by the scraper to fall free and avoid 'jamming the closure. As mentioned above, the position of door pivot 12 above and behind the body opening allows the topsurface of the door to move downwardly and rearwardly out of the path of the falling ore. In order to prevent injury to the door hinge by virtue of ore becoming lodged therein, we support the pivot 12 in an open manner as may be seen in Figs. 5 and 6 to allow ore to fall free of the pivot. Thus the body hinge ears 97 and the door hinge ears 98 are spaced apart to leave ample room for any ore which might tend to hang up at the pivot to fall free.

Since the dump scrolls 66 (Fig. 3) impart dumping movement to the skip gradually the present skip can be brought into the scrolls faster than usual. The body travels a short vertical and horizontal distance in the scrolls to reach the full dump position at an angle which is much steeper than ordinarily found. The steep dump angle in combination with the straight walls insures a clean, fast dump, and L the ability to bring the skip into and out of the scrolls rapidly with little travel adds to the time saved.

As pointed out above, the smooth action in the scrolls reduces the strain on the headframe and guide timbers (the tremendous kick or blow delivered to the timbers by a conventional skip is eliminated) with the savings noted. The steep dump angle keeps most of the load on the rope to maintain better counterbalancing. The reduced vertical height required in the headframe is of importance in new or old shafts.

It will be appreciated that a bottom dump skip must be free from leakage in transit and while dumping. In addition to effecting a watertight seal for the bottom door, the door must be provided with a safe, fast operating mechanism which holds the load safely and has desirable door opening characteristics. The toggle mechanism described above holds the door shut until the body is over the bin, at which time it opens at a progressively faster rate. The entire door apparatus may be adjusted to suit the characteristics to the installation, and the mechanism is readily accessible for maintenance and repair. The toggle action has a further advantage in that the weight of the ore on the door acts to hold the door shut rather than tending to open the door. When it is realized that 15 tons of ore may rest on the door, the desirability of such positive action will be apparent.

It will be appreciated that various changes may be effected in the instant design without departing from the spirit of the invention.

6 Therefore this invention is not to be limited to the disclosed embodiment but is to be limited only by the scope of the claims.

We claim:

1. A bottom dump skip comprising, a stringer adapted to be guided by the shaft timbers and to support a skip body, a skip body pivotally supported in said stringer adjacent its upper end to permit the bottom of the body to swing forwardly of the stringer, said body having straight interior walls and an open bottom, a door pivotally mounted at the rear of the body and adapted to seat on said bottom, and an arm pivotally connected to said stringer and to said door to actuate the door in response to the pivotal movement of the skip body relative to the stringer, said pivotal connection between the arm and the door, when the door is closed, being disposed rearwardly of an imaginary line drawn between the skip pivot and the pivotal connection between the arm with the stringer, and movable forwardly across said line as the door opens thereby to provide a toggle action for the opening and closing movements of the door as the skip swings forwardly and rearwardly on its pivot.

2. A skip according to claim 1 in which the pivotal connection between said arm and said stringer is carried on a parallel linkage swingable about axes parallel to the axis of the pivotal connection between the arm and the stringer for permitting of vertical and transverse adjustment of the location of the pivotal connection for proper toggle action, and means for adjusting the location of the pivotal connection between the arm and the stringer.

3. In a skip according to claim 2, metal-torubber seal means between the door and said bottom to prevent leakage when the door is closed, the adjustability of the pivotal connection between said arm and said stringer per-. mitting said seal means to be maintained tight.,

4. A skip according to claim 1 provided with skirts depending from the body to prevent lat-. eral spillag as the door opens, scraper means; carried by said door to scrape ore from the interior skirt surfaces as the door closes, and lat-- eral openings above said skirts to permit ejec-- tion of ore scraped from the skirts.

5. A skip according to claim 4 in which said skirts are slightly spaced laterally of the side walls of the skip and said scraper means project above the bottom of said body and between the exterior of the body and said skirts when the door is closed against the bottom of the body.

6. A bottomv dump skip having an open-ended body, a door for the bottom of the body, said door being connected to the body by means of a hinge positioned upwardly and rearwardly of the bottom of the body, a rubber seal depending from the bottom front edge of the body to serve as a seat for the door, the sides of the door projecting above the bottom of the body on the outside of the body when the door is seated on said seal, and the back of the door contacting the bottom back edge of the body.

7. A skip comprising,'a stringer frame adapted to be guided by the shaft timbers, an open-ended body of substantially uniform cross-section pivotally supported adjacent its upper end in said frame for swinging movement to a dumping position, dump rollers on said body adapted to engage stationary dump scrolls to swing the body to the dump position as the stringer frame is raised, a door pivotally mounted to seat on the bottom of the body, and-toggle :acting arms pive otally connected betweenzthesdoonandzthe,frame for operating the door as the'body swings to and from the dump position, the pivot pointsiofwsaid arms with the door being :disposed, when the door is closed, rearwardly of an imaginary line drawn between the skip pivot and the axis of the pivotal connection of the arms with the stringer frame and movable forwardly across said line as the door moves to open position, whereb the arms act to hold the door closed in the initial portion-of theabody movement to the dump position and to open-the door at a progressively more rapidzr ate in the final portion.

8. A skip comprising, a stringer adapted to be guided by'the-shaft timbers, an open-ended body of substantially uniform cross-section pivotally supported in said stringer adjacent its upper end and rearwardly of its center of gravity, stop means mounted on said-stringer below the body pivot to prevent movement of the body rearwardly into the stringer beyond its vertical position, dump rollers on the sides-of said body for engaging rdump; scrolls in the 'headframe :to pivot the body rforwardly tout 10f the :stringer, a door pivotally 'mounted on the bottom of the body to close same, :and a toggle arm'connected to :said

5 door vand to :said stringer to actuate the door in response to body movement.

ALEXANDER FINLAY. JAMES W. CLARK.

1o Iteferencesfiited in the-fileof this patent UNITED "STATES PATENTS Number Name Date 1,496,007 Lepley June 3, 1924. 13720388 Alexander July 9, 1929 2,424,620 Korn July 29, 1947 2 ,479,449. Woodward et a1. Aug. :16, 1949 2,5451% Saunders Mar. '13, 1951 FGREIGN PATENTS 20 Number Country Date 408,734' Germany Jan. '2 1, 1925 431,179 Germany July 1, 1926 

